Device for applying a treatment liquid to a web

ABSTRACT

An application device having a trough tapering downward in a wedge shape, through which a web is guided vertically from top to bottom, and which is sealed at the lower end by means of a horizontal hose. The hose abuts against the web from one side, while the web slips along on the opposite side at the lower end of the side surface of the trough. The side surface is formed on a counter-bearer, which is concave at its lower side, so that a deflection roller arranged beneath it can be set as high as possible, and the free web section from the hose gap to the contact point on the deflection roller is as short as possible.

BACKGROUND OF THE INVENTION

The invention relates to a device for the simultaneous application oftreatment liquid to both sides of a web, particularly a textile web.

Devices of this general type are disclosed in DE-PS 14 60 265 and DE 3733 996 C2. In the known embodiments, arranged in the "opposite sidesurface" of the trough, opposite an inflatable hose, is another suchinflatable hose, so that the web passes between the two hoses. Theadditional hose results in a space requirement corresponding to itscross-section on its side, so that design freedom is limited at thislocation.

In the device disclosed in DE-PS 14 60 265, the web continues to runvertically downward after passing by the interacting hoses, and passesthrough a pair of squeezer rollers, in which applied treatment liquid isat least partially squeezed out. In DE 37 33 996 C2, the web alsocontinues vertically downward after passing by the hoses, and is thenguided via a deflection roller after a certain distance.

There are treatments of textile webs in which the web demonstrates astrong tendency to shrink after the treatment liquid is applied. This isparticularly pronounced when cotton material is saturated with analkaline solution, as is the case in the mercerization process.

In mercerization, the strong tendency toward shrinkage is counteractedin that, after the mercerization solution is applied, the web is held ina so-called bound web guidance in which the web is guided over asequence of deflection rollers which rest against one another orvirtually rest against one another, and no free web sections whatsoeveroccur between the deflection rollers. The web is held tightly on thecircumference of the deflection rollers, as a result of the frictionwhich comes about from the web tension, in an effort to preventshrinkage.

A characteristic of the application devices of the type set forth aboveis the possibility of saturating the web with a relatively high amountof treatment liquid, in the range of 100 to 200% of the mass per unitarea. The web is uniformly wiped off at the hoses, and exits theapplication device with a charge which cannot be easily achieved withother application devices. At the same time, the charge is present onboth sides and is actually massaged slightly into the interior of theweb when it passes through the slit between the hoses.

It has been shown that if mercerization solution is applied to a textileweb with an application device of the type known in the prior art,shrinkage occurs virtually spontaneously. The free web sections whichresult from DE-PS 14 60 265 and DE 37 33 996 C2 result in unacceptableshrinkage amounts when the application device is used in such a way.

SUMMARY OF THE INVENTION

The object of the present invention is to develop an application deviceof the general type discussed above in such a way that the free sectionwhich exists after the web leaves the gap at the hose arrangement priorto its arrival at a bound web guidance becomes as short as possible.

This objective is attained via a device for simultaneously applyingtreatment liquid to both sides of a web, (particularly a textile web),in which a trough extends over the width of the web and has fixed sidesurfaces that, when viewed in a vertical plane transverse to the web,present a cross-section that tapers downwardly in a wedge shapenarrowing towards a wedge tip. The side surfaces are wider than the webthey bound and have ends that are connected to cross-walls forming aliquid-tight seal with respect to the side surfaces. One of the sidewalls is the wall of a counter-bearer and has, at its lower end, aclosed smooth section of wall defining a contact region against whichthe web can be pressed. There is further provided a horizontallydisposed hose which is arranged in a region of the wedge tip in an openrecess in one of the side walls, and which can be inflated in thedirection of the opposite side wall formed on the counter-bearer. Afurther device supplies treatment liquid to the trough. A web guidancemechanism is used for guiding the web vertically from the top downward,through the trough and the gap between the hose and the opposite sidesurface of the trough. The web is clamped in place between the hose andthe opposite side surface of the trough, the trough being sealed towardthe bottom by the action of the hose and the web. The web is wiped bythe hose as it passes the hose and the lower portion of the wallopposite the hose to a specific charge of treatment fluid, which can beselected in accordance with the inflation pressure of the hose. Adeflection roller having an outer working surface is arranged below thecounter-bearer and provides a surface against which the web is guidedvertically downward out of the hose gap and against which the web rests.The counter bearer has a lower side that is positioned adjacent thedeflection roller so as to minimize the distance the length of webbetween the deflection roller and the hose.

It has been found that affixing the inflatable hose on only one sidedoes not result in any loss in application quality and sealing of thetrough toward the bottom. This saves space on the side opposite theexisting hose, permitting the deflection roller to be moved as close aspossible to the hose gap.

The counter-bearer has the shape of a box-bearer, and has a concavelower side which is adapted in radius to the circumference of thedeflection roller and which is formed by the one tip, opposite the hose,which engages down in the wedge-shaped opening between thedownward-running web and the deflection roller which is tangential toit. In this way, the deflection roller can be placed as high aspossible, so that the section from the hose gap to the deflection rolleris short.

In a preferred embodiment, the deflection roller is driven, in order tothereby be able to pull the web through the hose gap, and, at the sametime, to exert a lengthwise tension to counteract the lengthwiseshrinkage of the web likewise occurring.

According to another aspect of this invention, the deflection roller isbut the first roller of a downstream treatment segment of the apparatusproviding the web with bound guidance. In this manner, a transition canbe made practically directly from charging the web with the treatmentliquid, particularly a mercerization solution, to a treatment segmentwith bound web guidance. A relatively large amount of treatment liquidcan be applied which, avoiding a significant free web section, entersimmediately into the bound web guidance and can dwell there.

According to a further aspect of the invention, the upper rollers arepartially arranged in gaps in the lower rollers (as is known in thefield) so as to provide a meander about which the web can travel withoutany free lengths of web between the rollers. This is especially usefulin subsequent treatment segments, e.g., as is done in mercerizationmachines.

An important characteristic with respect to the large amounts oftreatment liquid that may be applied and the virtually direct transitioninto the bound web guidance provided by the apparatus is the use ofmountings that permit the upper rollers to be lifted off of two adjacentlower rollers. By being able to lift the upper rollers in the usualmercerization roller sequence, squeezing can be avoided at thetransition from one deflection roller to the next, and the effect of thelarge application of treatment liquid can be maintained over at leastpart of the subsequent treatment segment in the bound web guidance. Theresult achieved with the application device and the arrangement of thedeflection roller, namely the high charge and the practically directtransition into the bound web guidance, thus can have its full effect.The relatively large amount of treatment liquid on the web has anopportunity to act on it over a longer dwell segment.

The mountings of the upper rollers can permit free self-adjustment ofthe upper rollers relative to the adjacent lower rollers in eachinstance. The upper rollers are therefore not rigidly mounted, butrather "loosely" mounted, i.e. they are guided rather than mounted, andcan thus find their optimum contact position.

It can be advantageous for at least one more of the lower rollers whichfollow the deflection rollers to be driven, in order to be able to bringabout not only a bound web guidance to avoid crosswise shrinkage, butalso a certain lengthwise stretching of the web, at least at somepoints. A prerequisite for this is, of course, that the driven lowerroller in question and the following upper roller do not touch to form aroller nip.

The drawing shows an exemplary embodiment of the invention in schematicform.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an application device constructedaccording to the principles of the invention;

FIG. 2 is a partial cross-sectional view of the application device takenalong Line II--II of FIG. 1; and

FIG. 3 is a side view of the application device with a subsequenttreatment segment.

DETAILED DESCRIPTION

In the application device 100 shown in FIG. 1, a textile web 1 made ofcotton material is guided over a spreader roller 2 and an upperdeflection roller 3, in order to be guided from there, in a section 1'which runs vertically downward, through a trough 4 containing atreatment liquid 5. Trough 4 extends at least over the width of web 1and possesses a flat left side surface 4' as seen in FIG. 1 and asimilarly flat right side surface 4", which approach one anotherdownwards, forming a wedge-shaped cross-section in a vertical planetransverse to web 1. Side surfaces 4' and 4" are arranged symmetricallyto web section 1, which forms a vertical plane, so that when web 1passes through trough 4, it is charged with treatment liquid on bothsides.

Left side surface 4' is formed by a carrier 6, which in turn issupported on a carrier beam 7 in the form of a hollow-profile beam witha square cross-section. In a vertical plane transverse to web 1, carrier6 has the cross-sectional shape evident in FIG. 1. In a recess 8 whichis open toward the right in FIG. 1, i.e. toward web 1, an inflatablehose 9 which extends horizontally over the width of web 1 is arranged;it can be filled with compressed air at a controllable pressure via anexternal connection 10, and bulges out slightly from recess 8, towardthe right in FIG. 1, under the pressure.

Side surface 4" of trough 4 which lies opposite hose 9 is formed by thewall of a box-shaped counter-bearer 11, which also extends over thewidth of the web. In at least region 4'" opposite hose 9, it is made ofpolished, corrosion-resistant steel having good sliding properties forweb 1 so as to provide a smooth, closed sliding surface for it. Formedbetween hose 9 and region 4'" is hose gap 12, through which web 1passes.

At the rigid and smooth lower region 4'" of side wall 4", web 1 readilyslips by on this side of hose gap 12. In order to improve the slip atflexible hose 9, a foil 18 of thin, corrosion-resistant sheet metal isprovided, which extends over the width of the web and is clamped inplace, by means of screw 15, between the upper region of side wall 4'and the sheet-metal guide provided there. Slip foil 18 extends downwardbeyond side wall 4', in front of hose 9, through hose gap 12, sags inthe form of a free loop below hose gap 12, and is fixed in place thereon a holder 19.

Hose gap 12 delimits trough 4 toward the bottom. At the two ends oftrough 4, there is a delimitation by means of end plates 13, which areattached in the manner indicated, by means of screws 14, on the faces ofthe counter-bearer, forming a seal, and which form cross-walls whichextend to the opposite side surface 4' of carrier 6. The carrier reachesbeyond the face of counter-bearer 11 in each instance. This also holdstrue for slip foil 18, which rests against side surface 4' and ispressed against it to form a seal by face 13' of end plate 13 in eachinstance, in which a seal can be arranged (FIG. 2).

Inflatable hose 9 presses web 1 against lower region 4'" of side surface4". As web 1 passes through hose gap 12, it is stripped or wiped on bothsides to a relatively high moisture content, determined by the pressurein hose 9. The moisture content can amount to 100 to 200% of the massper unit area of the dry goods.

Trough 4 contains only a small amount of treatment liquid, which isconstantly renewed. To this end, attached at the upper ends of sidesurfaces 4' and 4", by means of screws 15, are angled sheet-metal guides16 which form run-off surfaces 16' that are inclined toward trough 4,and on whose upper edge the treatment liquid is applied from feed lines17; as the treatment liquid flows down over run-off surfaces 16, itforms a uniform film which flows, in a laminar flow, along side surfaces4', 4" into trough 4.

After web 1 has passed through trough 4 and hose gap 12, it continues onits way below hose gap 12, vertically downward in a section 1", whichextends to contact point 1'" on the circumference of a deflection roller20 arranged below counter-bearer 11. Web 1 then wraps around deflectionroller 20 in its lower region and is located on it in "bound guidance",i.e. it is held in place on the roller by contact friction and cannotshrink freely. Section 1" is an unavoidable free web section, whichshould be designed to be as short as possible.

In order to minimize the length of free web section 1", lower side 21 ofcounter-bearer 11 is designed to be concave, corresponding to the outerperpheral surface of deflection roller 20, and arranged directly abovethis surface. As a result, deflection roller 20 can be set higher, inorder to bring contact point 1'" as close as possible to hose gap 12. Inits cross-section, counter-bearer 11 forms a tip 22, which reaches downinto the wedge-shaped opening between section 1" of the web and thecircumference of deflection roller 20, and there, at the lower end ofside wall 4", has region 4'" of slipping contact with web 1, and formshose gap 12. In this manner, section 1" of web 1 becomes as short as ispossible for a design with a trough 4 formed of fixed side surfaces 4',4".

FIG. 3 shows the interaction of application device 100 with a subsequenttreatment segment 200 providing bound web guidance. Treatment segment200 is comprised of a sequence of deflection rollers. These compriselower rollers 20, 30, and 40, arranged parallel to one another in ahorizontal plane, of which lower roller 20 is formed by deflectionroller 20 of FIGS. 1 and 2, lower rollers 20 and 40 being driven in theillustrated embodiment. Lower rollers 20, 30, and 40 have the samediameter and are set at equal distances from one another, which are lessthan the diameter. Provided in the gaps between lower rollers 20 and 30,and 30 and 40, respectively, are non-driven upper rollers 25 and 35 ofthis diameter as well. The web is guided over the sequence of deflectionrollers 20, 25, 30, 35, 40, . . . in meander shape, and has no free websection in treatment segment 200. Upper rollers 25 and 35 can restagainst lower rollers 20, 30, 40 at points 26, 36, 46 and 56, and theyare mounted "loosely", i.e. they can find their contact position bythemselves. Here, points 26, 36, 46 and 56 form roller nips at which web1 experiences linear force. This can be undesirable in certain cases,for example if the relatively large amount of treatment liquid appliedin application device 100 is not supposed to be squeezed out again rightaway.

For this purpose, journals 27 and 37 of upper rollers 25 and 35 aremounted in elbows 24 and 34, which can be lifted and lowered in thedirection of arrows 23. Lifting can be performed to such an extent thatupper rollers 25 and 35 are just lifted off the lower rollers at points26, 36 and 46, 56, respectively, so that bound web guidance is notreally given up, but nevertheless no roller nip with a squeezing linearforce is formed. In the lowered state, the loose mountings symbolized byelbows 24 have only a guidance function, and upper rollers 25, 35actually rest against lower rollers 20, 30 and 30, 40, respectively,creating a linear force.

When upper rollers 25 and 35 are lifted, the web, with a high charge,can make a transition into the bound web guidance practicallyimmediately, and can remain, with the charge, in treatment segment 200without being squeezed.

What is claimed is:
 1. A device for simultaneously applying treatmentliquid to both sides of a web, comprising:a trough extending over thewidth of the web, said trough having fixed side surfaces that, whenviewed in a vertical plane transverse to the width of the web, present across-section that tapers from a top portion of said trough downwardlyin a wedge shape to a wedge tip formed in a bottom portion of saidtrough, the side surfaces being wider than the web and having ends thatare connected to cross-walls forming a liquid-tight seal with respect tothe side surfaces, wherein one of the side surfaces is the wall of acounter-bearer and has, at its lower end, a closed smooth section of thewall defining a contact region against which the web can be pressed; ahorizontally disposed hose which is arranged in a region of the wedgetip in an open recess in one of the side walls, and which can beinflated in the direction of the counter-bearer, wherein only one of theside surfaces has the recess and the hose contained therein; a devicefor supplying treatment liquid to the trough; a web guidance device forguiding the web vertically downward from the top of said trough to a gapbetween the hose and the wall of the counter bearer, the web beingpressed in place between the hose and the opposite side surface of thetrough, and the trough being sealed toward the bottom, wherein the hosecooperates with the wall of the counter bearer such that the web iswiped by the hose as it passes the hose to a specific charge oftreatment fluid, which can be selected in accordance with the inflationpressure of the hose; and a deflection roller having an outer workingsurface, the deflection roller being arranged below the counter-bearerand providing a surface against which the web is guided verticallydownward out of the hose gap and against which the web laterally rests,wherein the counter bearer has a lower side that is positioned adjacentthe deflection roller so as to minimize distance between where the webcontacts the hose and then the deflection roller.
 2. A device as setforth in claim 1, wherein the counter-bearer has a generally box shapein cross-section, and has a concave lower side which is arrangeddirectly above the outer working surface of the deflection roller.
 3. Adevice as set forth in claim 2, wherein the curvature of the concavelower side of the counter-bearer matches the curvature of the deflectionroller.
 4. A device as set forth in claim 2, further comprising meansfor driving the deflection roller.
 5. A device as set forth in claim 1,further comprising means for driving the deflection roller.
 6. A deviceas set forth in claim 5, wherein the deflection roller is first withrespect to a travel path of the web of a series of rollers in asubsequent treatment segment that provides bound guidance to the web. 7.A device as set forth in claim 6, wherein the series of rollers in thetreatment segment comprises lower rollers separated from one another bygaps and upper rollers that are arranged so that they extend partiallyin said gaps, the upper and lower rollers each having a top and bottomsurface and being arranged so that they provide a path about which theweb is guided in meander shape around the bottom of the lower rollersand around the top of the upper rollers, in such a way that there are nofree web sections between the upper and lower rollers which areadjacent.
 8. A device as set forth in claim 7, further comprising ameans for driving at least one or more of the lower rollers which arearranged downstream from the deflection roller with respect to thetravel path of the web.
 9. A device as set forth in claim 7, wherein theupper rollers are placed on mountings that permit the upper rollers tobe lifted off of two of the lower rollers which are adjacent to oneanother.
 10. A device as set forth in claim 9, wherein the mountings ofthe upper rollers permit free self-adjustment of the upper rollersrelative to the lower rollers which are adjacent to one another.
 11. Adevice as set forth in claim 10, further comprising a means for drivingat least one or more of the lower rollers which are arranged downstreamfrom the deflection roller with respect to the travel path of the web.12. A device as set forth in claim 1, wherein the deflection roller isfirst with respect to a travel path of the web of a series of rollers ina subsequent treatment segment that provides bound guidance to the web.13. A device as set forth in claim 1, wherein the web is a textile web.